High-Temperature Oxidation of High-Entropy FeNiCoCrAl Alloys

High-Temperature Oxidation of High-Entropy FeNiCoCrAl Alloys

GUMEN Olena, KARPETS Myroslav, SMAKOVSKA Ganna, YAKUBIV Mykola

Abstract. Phase composition and mechanical properties and the formation of oxide layers on Fe40-xNiCoCrAlx (x = 5 and 10 at.%) alloys in long-term oxidation at 900 and 1000°C were studied. In the initial cast state, depending on the aluminum content and valence electron concentration, the alloys contain only an fcc solid solution (VEC = 8 e/a) or a mixture of fcc and bcc phases (VEC = 7.75 e/a). Thin continuous oxide scales containing Cr2O3 and NiCr2O spinel formed on the surface of both alloys oxidized at 900°C for 50 h. A further increase in the annealing time to 100 h leads to the formation of aluminum oxide Al2O3 in the scale on the Fe30Ni25Co15Cr20Al10 alloy, having high protective properties. An increase in the oxidation temperature to 1000°C results in partial failure of the protective layer on the alloy with 10 at.% Al. Long-term holding at 900°C (100 h) + 1000°C (50 h) does not change the phase composition of the Fe35Ni25Co15Cr20Al5 alloy matrix, being indicative of its high thermal stability. In the two-phase Fe30Ni25Co15Cr20Al10 alloy, the quantitative ratio of solid solutions sharply changes: the amount of the bcc phase increases from 4 to 54 wt.% and its B2-type ordering is observed. The mechanical characteristics of the starting alloys and those after long-term high-temperature annealing were determined by automated indentation. The hardness (HIT) and elastic modulus (E) of the cast Fe35Ni25Co15Cr20Al5 alloy are equal to 2 and 147 GPa, respectively, and decrease to 1.8 and 106 GPa after a series of long-term annealing operations. The Fe30Ni25Co15Cr20Al10 alloy shows the opposite dependence: HIT increases from 2.5 in the initial state to 3.1 GPa after annealing and E decreases from 152 to 134 GPa. This indicates that the Fe30Ni25Co15Cr20Al10 alloy is promising as a high-temperature oxidation-resistant and creep-resistant material.
Introduction

Keywords
High-Entropy Alloy, Valence Electron Concentration, Oxidation, Solid Solution, Ordering, Automated Indentation, Hardness, Microstructure

Published online 9/1/2023, 11 pages
Copyright © 2023 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: GUMEN Olena, KARPETS Myroslav, SMAKOVSKA Ganna, YAKUBIV Mykola, High-Temperature Oxidation of High-Entropy FeNiCoCrAl Alloys, Materials Research Proceedings, Vol. 34, pp 24-34, 2023

DOI: https://doi.org/10.21741/9781644902691-4

The article was published as article 4 of the book Quality Production Improvement and System Safety

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

References
[1] T.M. Butler, M.L. Weaver. Investigation of the phase stabilities in AlNiCoCrFe high-entropy alloys, J. Alloys Compd. 691 (2017) 119-129. https://doi.org/10.1016/j.jallcom.2016.08.121
[2] T.M. Butler, M.L. Weaver. Oxidation behavior of arc-melted AlCoCrFeNi multi-component high-entropy alloys, J. Alloys Compd. 674 (2016) 229-244. https://doi.org/10.1016/j.jallcom.2016.02.257
[3] T.M. Butler, M.L. Weaver, Influence of annealing on the microstructures and oxidation behaviors of Al8(CoCrFeNi)92, Al15(CoCrFeNi)85, and Al30(CoCrFeNi)70 high-entropy alloys, Metals 6 (2016) art.222. https://doi.org/10.3390/met6090222
[4] S.A. Firstov et al. Structural features and solid-solution hardening of the high-entropy CrMnFeCoNi alloy, Powder Metall. Met. Ceram. 55 (2016) 225-235. https://doi.org/10.1007/s11106-016-9797-9
[5] S.A. Firstov et al. Effect of electron density on phase composition of high-entropy equiatomic alloys, Powder Metall. Met. Ceram. 54 (2016) 607-613. https://doi.org/10.1007/s11106-016-9754-7
[6] S.A. Firstov et al. New class of materials – high-entropy alloys and coatings, Vestn. Tomsk. Gos. Univ. 18(4) (2013) 1938-1940.
[7] S.A. Firstov et al. Effect of the crystallization rate on the structure, phase composition, and hardness of the high-entropy AlTiVCrNbMo alloy, Deform. Razrush. Mater. 10 (2013) 8-15.
[8] M.C. Gao, D.E. Alman. Searching for next single-phase high-entropy alloy compositions, Entropy 15 (2013) 4504-4519. https://doi.org/10.3390/e15104504
[9] O. Gumen, I. Selina, R. Selin. Projection of phase composition of lowcost titanium alloy welded joints by finite element mathematical modelling method, Construction of Optimized Energy Potential 12, (2019), 51-56. https://doi.org/10.17512/bozpe.2021.1.07
[10] O. Gumen, I. Bilyk, M. Kruzhkova. Geometrical simulation of optimized vacuum-condensation spraying technology for titanium nitride on structural steel, LNCE 47 (2020) 103 110. https://doi.org/10.1007/978-3-030-27011-7_13
[11] G.R. Holcomb, J. Tylczak, C. Carney. Oxidation of CoCrFeMnNi high-entropy alloys, JOM 67 (2015) 2326-2339. https;//doi.org/10.1007/s11837-015-1517-2
[12] Y.F. Kao, S.K. Chen, T.J. Chen. Electrical, magnetic, and hall properties of AlxCoCrFeNi high-entropy alloys, J. Alloys Compd. 509 (2011) 1607-1614. https://doi.org/10.1016/j.jallcom.2010.10.210
[13] Y.-K. Kim et al. High-temperature oxidation behavior of Cr–Mn–Fe–Co–Ni high-entropy alloy, Intermetallics 98 (2018) 45-53. https://doi.org/10.1016/j.intermet.2018.04.006
[14] C.M. Lin, H.L. Tsai. Evolution of microstructure, hardness, and corrosion properties of high-entropy Al0.5CoCrFeNi alloy, Intermetallics 19 (2011) 288-294. https://doi.org/10.1016/j.intermet.2010.10.008
[15] S. Guo, C.T. Liu. Phase stability in high-entropy alloys: formation of solid-solution phase or amorphous phase, Prog. Nat. Sci. Mater. Int. 6 (2011) 433-446. https://doi.org/10.1016/S1002-0071(12)60080-X
[16] F.J. Wang et al. Cooling rate and size effect on the microstructure and mechanical properties of AlCoCrFeNi high-entropy alloy, J. Eng. Mater. Technol. 131 (2009) 345011 345013. https://doi.org/10.1115/1.3120387]
[17] W.R. Wang et al. Effects of Al addition on the microstructure and mechanical property of AlxCoCrFeNi high-entropy alloys, Intermetallics 26 (2012) 44-51. https://doi.org/10.1016/j.intermet.2012.03.005
[18] W.R. Wang, W.L Wang, J.W. Yeh, Phases, microstructure and mechanical properties of AlCoCrFeNi high-entropy alloys at elevated temperatures, J. Alloys Compd. 589 (2014) 143 152. https://doi.org/10.1016/j.jallcom.2013.11.084
[19] W. Kai et al. Air-oxidation of FeCoNiCr-based quinary high-entropy alloys at 700–900ºC, Corr. Sci. 121 (2017) 116–125. https://doi.org/10.1016/j.corsci.2017.02.008
[20] J.W. Yeh et al. Nanostructured high-entropy alloys with multiple principal elements: novel alloy design concepts and outcomes, Adv. Eng. Mater. 6 (2004) 299-303. https://doi.org/10.1002/adem.200300567